Package ucar.unidata.geoloc

Class Bearing

  • public class Bearing
extends Object
    Computes the distance, azimuth, and back azimuth between two lat-lon positions on the Earth's surface. Reference ellipsoid is the WGS-84 by default. You may use a default Earth (EarthEllipsoid.WGS84) or you may define your own using a ucar.unidata.geoloc.Earth object.

    • Constructor Detail

      • Bearing

        public Bearing​(double azimuth,
               double backazimuth,
               double distance)

    • Method Detail

      • calculateBearing

        public static Bearing calculateBearing​(Earth e,
                                       LatLonPoint pt1,
                                       LatLonPoint pt2)
        Calculate the bearing between the 2 points. See calculateBearing below.
        Parameters:
        e - Earth object (defines radius & flattening)
        pt1 - Point 1
        pt2 - Point 2
        Returns:
        The bearing

      • calculateBearing

        public static Bearing calculateBearing​(LatLonPoint pt1,
                                       LatLonPoint pt2)
        Calculate the bearing between the 2 points. See calculateBearing below. Uses default Earth object.
        Parameters:
        pt1 - Point 1
        pt2 - Point 2
        Returns:
        The bearing

      • calculateBearing

        @Deprecated
public static Bearing calculateBearing​(double lat1,
                                       double lon1,
                                       double lat2,
                                       double lon2,
                                       Bearing result)
        Deprecated.
        do not use

      • calculateBearing

        public static Bearing calculateBearing​(double lat1,
                                       double lon1,
                                       double lat2,
                                       double lon2)
        Computes distance (in km), azimuth (degrees clockwise positive from North, 0 to 360), and back azimuth (degrees clockwise positive from North, 0 to 360), from latitude-longituide point pt1 to latitude-longituide pt2. Uses default Earth object.
        Parameters:
        lat1 - Lat of point 1
        lon1 - Lon of point 1
        lat2 - Lat of point 2
        lon2 - Lon of point 2
        Returns:
        a Bearing object with distance (in km), azimuth from pt1 to pt2 (degrees, 0 = north, clockwise positive)

      • calculateBearing

        @Deprecated
public static Bearing calculateBearing​(Earth e,
                                       double lat1,
                                       double lon1,
                                       double lat2,
                                       double lon2,
                                       Bearing result)
        Deprecated.
        do not use

      • findPoint

        public static LatLonPointImpl findPoint​(Earth e,
                                        LatLonPoint pt1,
                                        double az,
                                        double dist,
                                        LatLonPointImpl result)
        Deprecated.
        will return LatLonPoint in 6.
        Calculate a position given an azimuth and distance from another point.
        Parameters:
        e - Earth object (defines radius and flattening)
        pt1 - Point 1
        az - azimuth (degrees)
        dist - distance from the point (km)
        result - Object to use if non-null
        Returns:
        The LatLonPoint
        See Also:
        findPoint(double,double,double,double,LatLonPointImpl)

      • findPoint

        public static LatLonPointImpl findPoint​(double lat1,
                                        double lon1,
                                        double az,
                                        double dist,
                                        LatLonPointImpl result)
        Deprecated.
        will return LatLonPoint in 6.
        Calculate a position given an azimuth and distance from another point. See details, below. Uses default Earth.
        Parameters:
        lat1 - latitude of starting point
        lon1 - longitude of starting point
        az - forward azimuth (degrees)
        dist - distance from the point (km)
        result - Object to use if non-null
        Returns:
        the position as a LatLonPointImpl

      • findPoint

        @Deprecated
public static LatLonPointImpl findPoint​(Earth e,
                                        double lat1,
                                        double lon1,
                                        double az,
                                        double dist,
                                        LatLonPointImpl result)
        Deprecated.
        use findPoint(Earth e, double lat1, double lon1, double az, double dist)

      • findPoint

        public static LatLonPoint findPoint​(Earth e,
                                    double lat1,
                                    double lon1,
                                    double az,
                                    double dist)
        Deprecated.
        will return LatLonPoint in 6.
        Calculate a position given an azimuth and distance from another point.

        Algorithm from National Geodetic Survey, FORTRAN program "forward," subroutine "DIRCT1," by stephen j. frakes. http://www.ngs.noaa.gov/TOOLS/Inv_Fwd/Inv_Fwd.html

        Original documentation: 

            SOLUTION OF THE GEODETIC DIRECT PROBLEM AFTER T.VINCENTY
    MODIFIED RAINSFORD'S METHOD WITH HELMERT'S ELLIPTICAL TERMS
    EFFECTIVE IN ANY AZIMUTH AND AT ANY DISTANCE SHORT OF ANTIPODAL
        Parameters:
        e - Earth object (defines radius and flattening)
        lat1 - latitude of starting point
        lon1 - longitude of starting point
        az - forward azimuth (degrees)
        dist - distance from the point (km)
        Returns:
        the position as a LatLonPointImpl

      • calculateBearing

        public static Bearing calculateBearing​(Earth e,
                                       double lat1,
                                       double lon1,
                                       double lat2,
                                       double lon2)
        Computes distance (in km), azimuth (degrees clockwise positive from North, 0 to 360), and back azimuth (degrees clockwise positive from North, 0 to 360), from latitude-longituide point pt1 to latitude-longituide pt2.

        Algorithm from U.S. National Geodetic Survey, FORTRAN program "inverse," subroutine "INVER1," by L. PFEIFER and JOHN G. GERGEN. See http://www.ngs.noaa.gov/TOOLS/Inv_Fwd/Inv_Fwd.html

        Original documentation:
        SOLUTION OF THE GEODETIC INVERSE PROBLEM AFTER T.VINCENTY
        MODIFIED RAINSFORD'S METHOD WITH HELMERT'S ELLIPTICAL TERMS
        EFFECTIVE IN ANY AZIMUTH AND AT ANY DISTANCE SHORT OF ANTIPODAL
        STANDPOINT/FOREPOINT MUST NOT BE THE GEOGRAPHIC POLE

        Reference ellipsoid is the WGS-84 ellipsoid.
        See http://www.colorado.edu/geography/gcraft/notes/datum/elist.html

        Requires close to 1.4 E-5 seconds wall clock time per call on a 550 MHz Pentium with Linux 7.2.

        Parameters:
        e - Earth object (defines radius and flattening)
        lat1 - Lat of point 1
        lon1 - Lon of point 1
        lat2 - Lat of point 2
        lon2 - Lon of point 2
        Returns:
        a Bearing object with distance (in km), azimuth from pt1 to pt2 (degrees, 0 = north, clockwise positive)

      • getAngle

        public double getAngle()
        Get the azimuth in degrees, 0 = north, clockwise positive
        Returns:
        azimuth in degrees

      • getBackAzimuth

        public double getBackAzimuth()
        Get the back azimuth in degrees, 0 = north, clockwise positive
        Returns:
        back azimuth in degrees

      • getDistance

        public double getDistance()
        Get the distance in kilometers
        Returns:
        distance in km